Física de Astropartículas as propriedades e técnicas de detecção dos Raios Cósmicos de Ultra-Alta Energia.

Size: px

Start display at page:

Download "Física de Astropartículas as propriedades e técnicas de detecção dos Raios Cósmicos de Ultra-Alta Energia."

Priscilla Stephens
6 years ago
Views:

1 Universidade Federal de Santa Catarina, Florianópolis, SC 14 de setembro de 2012 Física de Astropartículas as propriedades e técnicas de detecção dos Raios Cósmicos de Ultra-Alta Energia. Prof. Marcelo A. Leigui de Oliveira CCNH UFABC leigui@ufabc.edu.br

2 More than 100,000 cosmic rays will hit each of you during this lecture Artistic view of a cosmic rays shower. Credit: ASPERA/Novapix/L.Bret

3 What are Cosmic Rays? Cosmic Rays (CR) are high-energy particles of extraterrestrial origin Secondary CR (produced by the primaries in the Earth s atmosphere) consist of essentially all elementary particles and nuclei (both stable and unstable). The most important are Classical CR are nuclei or ionized atoms ranging from a single proton up to an iron nucleus and beyond, but being mostly protons (~90%) and particles (~9%). Including stable and quasistable particles: neutrons, antiprotons & (maybe) antinuclei, hard gamma rays (l < cm), electrons & positrons, neutrinos & antineutrinos, esoteric particles (WIMPs, magnetic monopoles, mini black holes,...)? nucleons, nuclei & nucleides, (hard) gammas, mesons (p ±,p 0,K ±,, D ±, ), charged leptons (e ±, m ±, t ± ), neutrinos & antineutrinos (n e, n m, n t ).

5 A short history of cosmic ray physics

6 1900 C.T.R. Wilson noticed that electroscopes lose their charges even if they were very well isolated from the neighbouring sources;

7 1900 C.T.R. Wilson noticed that electroscopes lose their charges even if they were very well isolated from the neighbouring sources;

8 1900 C.T.R. Wilson noticed that electroscopes lose their charges even if they were very well isolated from the neighbouring sources;

9 1900 C.T.R. Wilson noticed that electroscopes lose their charges even if they were very well isolated from the neighbouring sources; E. Rutherford hypothesised that most of the ionisation was due to natural radioactivity; but much more penetrating than natural radioactivity!

10 1910 T. Wulf who developed the best electrometers of that time, measured a fall from 22,25 ions/cm 3 s (~ sea level) to 15,7 ions/cm 3 s, at the top of the Eiffel Tower (330 m asl) but they should have halved in 80 m;

11 1912 Hess ascended in his balloon to 5 km (in an open ballon without oxygen!) and measured unambiguously an increase in ionisation (4 times more discharges at 4880 m): there must be a radiation of cosmic origin ionizing the atmosphere; Victor F. Hess after one of his successful flights in 1912.

13 1936 Hess & Anderson

15 1931 Auguste Piccard took off from Augsburg with a pressurized cabin to reach a record altitude of 15,785 m. During this flight, Piccard was able to gather substantial data on the upper atmosphere, as well as measure cosmic rays. In 1932, launched from Zürich to made a second record-breaking ascent to 16,200 m. He ultimately made a total of twenty-seven balloon flights setting a final record of 23,000 m.

During this flight, Piccard was able to gather substantial

In 1932, launched from Zürich to made a second record-breaking

He ultimately made a total of twenty-seven balloon flights

16 1931 Auguste Piccard took off from Augsburg with a pressurized cabin to reach a record altitude of 15,785 m. During this flight, Piccard was able to gather substantial data on the upper atmosphere, as well as measure cosmic rays. In 1932, launched from Zürich to made a second record-breaking ascent to 16,200 m. He ultimately made a total of twenty-seven balloon flights setting a final record of 23,000 m G. Pfotzer used three-fold coincidences of GM tubes to measure intensities up to 28 km

17 1948 J.A. Van Allen used single GM tube aboard a V-2 rocket to measure intensities up to 161 km.

19 Back in 1938:

31 1 ev = 1,6 x J 1J = 6,25 x ev 1 x ev = 16 J

Some EAS arrays: Volcano Ranch, USA (1959-1962); Haverah Park, UK (1968-1987); SUGAR, Australia (1968-1979); Yakutsk,

++); Kascade, Germany (1995 ++); Pierre Auger Observatory, Argentina (2001++).

32 Some EAS arrays: Volcano Ranch, USA ( ); Haverah Park, UK ( ); SUGAR, Australia ( ); Yakutsk, Russia ( ); Akeno, Japan ( ); AGASA, Japan ( ); EASTOP, Italy ( ); CASA/MIA, USA ( ); Kascade, Germany ( ); Pierre Auger Observatory, Argentina (2001++) The AGASA Group in Japan and the Yakutsk group in Russia each reported an event with an energy of 2x10 20 ev. Pierre Auger Observatory: taking data since 2004

38 Other measurement techniques

39 Fluorescence and Cherenkov Lights Air Fluorescence Detector Emission Propagation Detection

40 Cherenkov Light Provided that : v c c / n, where n is theindex of refraction : E E th m which is in air ( n 11/ n air ) for electrons : E 21MeV The totalamount of energy radiated per unit length is : de dx q 2 4 vc / n( ) ( ) 1 v 2 2 c d 2 n ( )

41 Cherenkov Radiation in the Atmosphere

Some air Cherenkov experiments: CANGAROO, Australia (1992++); CAT,

Telescope(s), India (2005++); HEGRA, Canary Islands (1992-2002);

(2003++); VERITAS, USA (2007++); CTA project.

42 Some air Cherenkov experiments: CANGAROO, Australia (1992++); CAT, France (1996++); CLUE, Canary Islands ( ); HAGAR Telescope(s), India (2005++); HEGRA, Canary Islands ( ); HESS, Namibia (HESS-I 2002, HESS-II 2012); MAGIC, Canary Islands (2003++); VERITAS, USA (2007++); CTA project. HESS I and HESS-II: four 12 m telescopes and one 28 m telescope VERITAS: four 12 m telescopes MAGIC: a 17 m telescope

43 Cherenkov Radiation in the Atmosphere

44 Cherenkov Radiation in the Atmosphere

45 Air Fluorescence Measured fluorescence spectrum in dry air at 800 hpa and 293 K F Arqueros, F Blanco and J Rosado, New J. Phys. 11 (2009) AIRFLY Collaboration, Astroparticle Physics, Volume 28, Issue 1, September 2007, Pages 41-57,

Some air fluorescence experiments: Fly s eye/hires, USA

ASHRA, Hawaii (2002++); Telescope Array (TA), USA (2006++);

in the USA observed a cosmic ray event with an energy of 3x10

47 Some air fluorescence experiments: Fly s eye/hires, USA (1981/ ); Pierre Auger Observatory, Argentina (2001++); ASHRA, Hawaii (2002++); Telescope Array (TA), USA (2006++); EUSO, ISS (2016) 1991 The Fly's Eye cosmic ray research group in the USA observed a cosmic ray event with an energy of 3x10 20 ev. The Telescope Array The Pierre Auger Fluorescence Detector

50 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV):

51 Fluorescence track reconstruction - monocular mode - stereo mode issues: - atmospheric transmission - fluorescence yield - Cherenkov subtraction

52 Horizontal attenuation monitors (range ~ 60 km) Steerable LIDARs Laser Shots (Central Laser Facility): light scattering Infrared Monitors (clouds) Cross-checks

53 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV): longitudinal development

54 The Shower Detector Plane t i T 0 R c p 0 tan i 2

55 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV): longitudinal development Cherenkov subtraction

56 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV): longitudinal development Cherenkov subtraction Gaisser-Hillas fit

57 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV): longitudinal development Cherenkov subtraction Gaisser-Hillas fit Energy

58 FD: 24 (+3) fluorescence telescopes (30 x 30 FOV): longitudinal development Cherenkov subtraction Gaisser-Hillas fit Energy 10% duty cycle almost calorimetric measurement

59 20 May 2007 E ~ ev

60 S 38 (1000) vs. E(FD) 661 hybrid events E a FD as b ( stat) 0.12( syst) b ( stat) 0.04( syst) 2 / ndf ev J. Abraham et al, Phys. Rev. Lett. 101, (2008)

61 hybrid SD only FD only Angular resolution Aperture independent of E, mass, models independent of E, mass, models dependent of E, mass, models and spectral slope Energy independent of mass, models dependent of mass, models independent of mass, models

62 Molecular Bremsstrahlung 1. EAS particles dissipates energy through ionization 2. A weakly ionized plasma is formed at T ~ 10 4 K 3. This plasma cools down very fast (10 ns) though collisions with air molecules 4. Bremsstrahlung from free electrons (f ~ GHz: microwave band)

63 Coherent Radio Emission 1. EAS produces e ± in the shower front (2-3 m thick) 2. These e ± bend in the geomagnetic field (~ 0.3 G), generating synchrotron radiation (geosynchrotron) 3. Emissions for all e ± add up coherently 4. The radiation can be detected by antennas at f ~ 100 MHz (FM band)

65 RESULTS FROM PIERRE AUGER OBSERVATORY

66 CMB: A. A. Penzias and R. Wilson, Astroph. J., 142 (1965) 419 K. Greisen, Phys. Rev. Lett., 16 (1966) 748 G. T. Zatsepin, V. A. Kuz'min, Pis'ma Zh. Eksp. Theor. Fiz. 4 (1966) 53 The GZK Cutoff

69 Science (Nov/2007)

72 (a) Photon shower (b) Proton shower (c) Iron shower

76 And what about the climate changes?

77 And what about the climate changes?

78 And what about the climate changes?

79 Muons telescope

80 Water Cherenkov Tank

81 Water Cherenkov Tank

89 Light pollution in Brazil:

90 Universidade Federal de Santa Catarina, Florianópolis, SC 14 de setembro de 2012 Obrigado! Prof. Marcelo A. Leigui de Oliveira CCNH UFABC

91 Universidade Federal de Santa Catarina, Florianópolis, SC 14 de setembro de 2012 Backup Slides Prof. Marcelo A. Leigui de Oliveira CCNH UFABC

92 Chemical composition of the atmosphere

93 2 / ' ' ' ') ( ) ( : above a given level integrated to thedensity corresponds And thedepth cm g t da dm dh dh da dm dh h h t t h h m cm g km h m cm g km h m cm g km h m cm g cm g t x t x t dx da dm dx da dm dv dm 2502 / 1 0,00326 / (asl) : 24,2 / 1 0,3376 / (asl) : 9,0 / 1 0,9075 / : (asl) 8,2 / 1 1,0000 / : level at thesea / Massthickness : Mass Thickness & Depth

94 Mass Thickness & Depth For an ideal, plane and isothermic atmosphere: t( h) t( h h ( h') dh' 0) H 0 h e 0 h'/ H 1032,6 g / cm dh' He 2 0 h/ H

99 Atmospheric layers 1. Troposphere*: 0 (7 18) km 2. Stratosphere*: km 3. Mesosphere: km 4. Thermosphere: km 5. Exosphere: > 480 km * most important for CRs physics

Chemical composition of the atmosphere Chemical composition of the atmosphere (without water), per volume ppmv: parts per million by volume Gas Volume Nitrogen (N 2 ) 780.

100 Chemical composition of the atmosphere Chemical composition of the atmosphere (without water), per volume ppmv: parts per million by volume Gas Volume Nitrogen (N 2 ) ppmv (78,084%) Oxygen (O 2 ) ppmv (20,946%) Argon (Ar) ppmv (0,9340%) Carbon dioxide (CO 2 ) 390 ppmv (0,0390%) Neon (Ne) 18,18 ppmv (0,001818%) Helium (He) 5,24 ppmv (0,000524%) Methane (CH 4 ) 1,79 ppmv (0,000179%) Krypton (Kr) 1,14 ppmv (0,000114%) Hydrogen (H 2 ) 0,55 ppmv (0,000055%) Nitrous oxide (N 2 O) 0,3 ppmv (0,00003%) Carbon monoxide (CO) 0,1 ppmv (0,00001%) Xenon (Xe) 0,09 ppmv (9x10 6 %) Ozone (O 3 ) 0,0 a 0,07 ppmv (0% a 7x10 6 %) Nitrogen dioxyde (NO 2 ) 0,02 ppmv (2x10 6 %) Iodine (I) 0,01 ppmv (10 6 %) Ammonia (NH 3 ) Traces Gases not included (dry air): Water vapor (H 2 O) ~0.40% throughout the atmosphere, usually between 1%-4% in the surface From Wikipedia

Electromagnetic waves: oscillating electric and magnetic

792.458 m/s 3 10 8 m/s the electromagnetic spectrum is

based on bands of frequency or wavelength within each band

101 Electromagnetic waves: oscillating electric and magnetic fields that travel in vacuum in the speed of light: c = m/s m/s the electromagnetic spectrum is continuous and we distinguish different types of waves based on bands of frequency or wavelength within each band different processes may occur, leading to different opacities to the waves

102 Radiation Balance on Earth

103 Electromagnetic Processes Pair production Creation of an elementary particle and antiparticle, usually when a photon interacts with a nucleus : E E th 2m c e MeV for the production of a pair electron - positron The total pair production cross - section : pair 2 ( k) 4Z r 2 e ln(191z ) 1 54

104 Electromagnetic Processes Bremsstrahlung Charged particles interact with nuclei electromagnetic field and generate photons. The energy loss is given by : de 4NZ( Z 1) 2 re E ln191z dx A where X is the radiation length E X 0,

105 Electromagnetic Processes Ionization loss The energy loss per unit of column depth is : de dx N AZ A 2 ze 2 mv 2 2 ln 2 2 2mv W 2 I 2 2, where Z, A and I are, respectively,the atomic, the mass number and theionization potentialof the medium, ze, v and m are, respectively,the charge the velocity and the mass of the particle. and characterizeparticle energy and momentum. W is the maximum energy loss.

106 Electromagnetic Processes Ionization loss An important correction where the logathimic has been made at the highest energies increase is supressed(density correction) : for denser media, de dx N AZ A ze 2 mv mv W ln 2 2 I

107 Electromagnetic Processes The Critical Energy ( ) is defined Bremsstrahlung rate. 0 as the energy at which the collision loss rate equals the For air : X g/cm MeV

108 Electromagnetic Processes

109 Electromagnetic Processes

The Pierre Auger Observatory

The Pierre Auger Observatory Hunting the Highest Energy Cosmic Rays I High Energy Cosmic Rays and Extensive Air Showers March 2007 E.Menichetti - Villa Gualino, March 2007 1 Discovery of Cosmic Rays Altitude